Gas blast circuit breaker



N0 9, 1948- H. THOMMEN GAS BLAST CIRCUIT BREAKER 2 Sheets-Sheet l Filed March 12, 1945 NOV 9 1948- H. THOMMEN GAS BLAST CIRCUIT BREAKER 2 Sheets-Sheet 2 Filed March 12, 1945 Patented Nov. 9, 1948 ons BLAST CIRCUIT BREAKER Hans Thommen, Baden, Switzerland, assignor to Aktiengesellschaft Brown, Boveri & Cie.,` Baden, Switzerland l Application March 12, 1945, Serial No. 582,255 In Switzerland September 11, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires September 11, 19.63

(Cl. D-148) 1o claims. 1

Gas blast circuit breakers with multiple interruption are known where the contacts are actuated by pressure gas and the arc at the contacts is extinguished by subjecting it to .a blast of pressure gas, and where at the same time an impedance (resistance or capacitance) is connected in parallel with the points of interruption, the voltage distribution over the points of interruption being controlled with the aid of this impedance. With this kind or circuit breaker it has been found that when currents of between a low and medium value are interrupted the arc voltage can assume high values, the voltages not being equal at all points of interruption. This results in an unequal voltage distribution over the points of interruption, and this in turn causes difiiculties in connection with the extinction of the arc at the various points of interruption which are arranged in series. These disadvantages can be overcome if higher control currents are employed for the impedances. These higher control currents have to be interrupted by a series switch point when the control resistance is disconnected, the isolation of the voltage also being dealt with by this switch. The usual kind of isolating switch is, however, no longer adequate for interrupting these higher control currents.

The present invention thus concerns a gas blast circuit Ibreaker with multiple interruption and voltage control of the compressed-gas operated isolated points of interruption by means of parallel impedances, whereby the disadvantages referred to are overcome according to the invention 'by the impedances being connected in parallel with the power interrupting points by special switching means. For circuit breakers with a resistance this is particularly advantageous because the resistance can be made so small that the circuit breaker can also be used for overvoltage protection at low currents. A further advantage is that the switching means for the partial resistances do not need to be dimensioned for a continuous current.

Various constructional examples of the invention are illustrated in the accompanying draw- `ings where Figs. 1 and 2 show two different dlagrams of connections for the circuit breaker, whilst Figs. 3 to 8 illustrate in diagrammatic form various possible constructional forms of circuit breakers with control resistances.

In all gures ai to as indicate the points of interruption of a multiple break gas Iblast circuit breaker, these points of interruption being arranged in series. For distributing the voltage over the points of interruption control resistances g1 to ge are connected in parallel with the points of interruption. The resistance can consist of a wire or .be made of ceramic material. As shown in Fig. 1 each point of interruption can have a part resistance connected in parallel with it, or as shown in Fig. 2 the impedances of several points of interruption can be combined to form a common ,disconnectable group.

The points of interruption a1, a2 etc. of the circuit breakers shown in Figs. 3 to 7 are equipped with self-closing contacts, one contact of each point being a spring-loaded pin contact which abuts against a nozzle-shaped hollow contact. The contacts of each point of interruption are enclosed in hollow insulators d1, d2 etc. with metallic top and bottom elements. The top and bottom elements support the contacts and are provided with passages for the flow of pressure gas to the contacts and also with outlet openings through which the gas from the contacts can be conducted away. The points of interruption are mounted on a foundation f by means of a hollow supporting insulator e consisting of one or more parts, whereby the foundation j can be used as a compressed gas container and if necessary be mounted on wheels. The control resistances g1 etc. together with their switching means are arranged in parallel with the points of interruption. These resistances g1 etc., together with their switching means are located inside hollow insulators i1, etc. with metallic bottom and top elements, these insulators being arranged in the form of a column next to the extinguishing chamer insulators of the points of interruption. The extinguishing chambers and the resistances are thus assembled in a similar manner. It is advisable to connect the hollow insulators contain ing the resistances and their switching means with the extinguishing chambers containing the points of interruption by means of common bottom and cover pieces k1 etc.` which contain the contact elements, as shown for instance in Fig. 3. By this means any number of switch elements can be assembled in column form.

The switching means for the resistances can consist of spark gaps with iixed or adjustable electrodes, or of switches with at least one moveable switch element. The switching means are preferably subjected to a pressure gas blast and are pneumatically operated. In this case the contacts for the resistance switching means are constructed in the same Way as the contacts of the power circuit breaker; that is they are opened by pressure gas and are closed automatically by a spring. The actuating and extinguishing pressure gas for the resistance switches can be taken from the extinguishing chambers containing the points of interruption. The pressure gas for switching the resistancemcan, however, also be teleco from a separate source. la the constructioral examples shown :lo the the gas y for the points oi interruption arid the swt tolling mesas flows through the cir@ breaker elements themselves, the switch gases being discharged tlcuough the ruetalllc bot ariel cover pieces.

With circuit breakers of the lourd shown irl il, when the malo. valve m is operated pres sure gas flows te the extinguishing chambers the points of interruption cios are :First opened and the are at these palets is subjected to gas blast. liter a slight delay caused by a thrcttling action of the irl the comparatively small passages connecting the extinguishing chambers rlich arid the hollow lilsulators this, switches crcz are their opened by the pressure and the resistauces @les are each distortl Elected separately. The lor actuating the contacts and extinguishing the arc thus also serves as au insulating and cooling medium ior the resistahces.

,.Ll. series disconnecting switch b as indicated in :l (brokers lines) is used for isolating the volt- .instead of having separate discharge passages ai, e2, ih. iilg.

fers from that ci Fig. Cl only irl so las as spart; gaps p1 to p3 are used as switching iceearls :lor the resistances o1 to g3 instead o switches, the opera= tion arid effect remaining the saaie also the application of sauce. The sparlr cari be pro-l vided with pin electrodes or with. e la. electrode ariel a hollow electrode. The spari can be subjected to a transverseor lorlgit blast. lt is also possible to locate the electrodes ci the spark gaps at each side of hostie made ci insulating material. Iii Fig. ll which shows the latter arrangement, the electrodes icriuirlg the gap pi are located ori opposite sides oi a sacarle t; the voltage control impedance is designated y1 as in the other embodiments previously described.

Fig. 6 shows a gas blast circuit breaker with spark gaps for switching the resistarices, where the switch gases from the points of interruption a1 to a3 are conducted away over the spari; gaps p1 to p3. This arrangement possesses the aol-= vantage that the coming into operation oi the spark gaps is accelerated by the gases which flow past, this being of importance where high powers are concerned.

Fig. '7 shows a modified forro. oi the invention where the components of the control resistance are fixed one above the other to an insulating tube q which is contained in an insulator r. The spark gaps are located inside tube q. Pressure gas is conveyed to the insulating tube q through pipe s from the arcing chambers d1 to da. After passing the spark gaps pi to p3 the pressure gas ows between the insulating tube q aud insulator r over resistance g1 to g3 and. out through ne to the atmosphere.

Circuit breakers constructed as shown in Figs. 4 to 7 can be used with or without a series disconnecting switch, just is as the case with the circuit breaker according to Fig. 3.

I claim:

l. In a circuit breaker, a plurality of normally closed sets of main contacts connected in series circuit relation and operable to open by the application of pressure gas thereto, a plurality of impedances in parallel circuit relation across said sets of main contacts to carry the current upon opening or the main contacts and for controlling the voltage distribution over said main contacts on opening thereof. said ia'lpedarlces having a relatively low magnitude to thereby draw a rela= tively high order of control current, and pres. sure gas operated switch means individual to each impedance connecting the same iii series circuit relation and adapted to interrupt the :dow of current therethrough.

z. A circuit breaker as deried in claim l wherein each o1? said impedarices bridges at least two sets ci said. series connected mais contacts when connected by the switch means associated there-1 with.

3. l circuit breaker as defined irl claim l wherein the switch means for each impedance is a spark gap, and arcs established across the gaps upon separation of the sets oi main contacts are thereafter extinguished by au application of pres'- sure gas thereto.

il. A circuit breaker as oleneci ih claim l wherein each of said switch means is cohstitutecl by relatively movable and normally closed nozzle and pin contacts separable under the aca tion oi pressure gas.

5. lll a circuit breaker, a vertical supporting insulator, a plurality of arcing chambers in axial alignment with and superposed upon said supen porting insulator, each said arcing chamber come prising a hollow insulator forming the circumm ierehtial wall of the chamber and metallic end plates forming the top and botto-rh. walls thereof, passageways through said plates placing said arcing chambers in communication. with each other for conducting pressure gas through the several chambers, a set of pressure gas actuated. load contacts ih each chamber, each Contact set including a spring loaded pin Contact cooperative with a hollow nozzle Contact and separable therem from under the action of the pressure gas, said pin and noazle contacts being carried respectively by the metallic end walls of the chambers, an impedance arid seri-es connected auxiliary pressure gas operated switch means for each set oi load contacts, said impedemces being of relatively low magnitude to thereby draw a high oroler o control current, an insulating member housing each said impedance and switch means, said irla sulating members being supported between lateral extensions on said end plates that also connect each impedance and switch in parallel with the associated set of load contacts, and means ari-1 mittihg pressure gas to the several insulating members subsequent to the opening of said sets of load contacts to open said auxiliary switch mearis.

t. A circuit breaker as dei-ined in claim 5 wherein the lateral extensions on said end plates include an internal passageway placing each of' said insulating members ih communication with the blast chamber associated therewith to receive pressure gas therefrom.

7. A circuit breaker as dened in claim 5 wherein the lateral extensions on said end plates each include an internal passageway placing the nozzle contact of each set oi load contacts in communication with the blast chamber and auxiliary switch means associated therewith to receive pressure gas therefrom.

8. A circuit breaker as defined in claim 5 wherein each of said auxiliary switch means is constituted by an arc gap in which the arc is interrupted by pressure gas to switch the impedance out of circuit with the associated set of load contacts.

9. A circuit breaker as defined in claim 5 wherein each of said auxiliary switch means includes a nozzle contact, said end plates intermediate adjacent sets of load contacts include a pressure gas exhaust outlet, and the lateral extensions oi such end plates include a pair of internal passageways, one of said passageways placing the nozzle contact of the switch means in the insulating member supported thereon in communication with the gas outlet therein, and the other passageway placing the blast chamber of which it forms the top end wall in communication with the associated insulating member.

10. A circuit breaker as defined inl claim 5 wherein the switch means for each impedance is constituted by an arc gap formed by electrodesV arranged on opposite sides of a, nozzle of insulating material through which the pressure gas is passed.

HANS THOMMEN.

REFERENCES CITED The following'references are of record in the file of this patent:

UNITED STATES PATENTS Great Britain 1900 

